Andrew Busch, global currency and public policy strategist for BMO Capital, thinks Germany is likely to pass the package, but warns that dire things could happen if they don't, and Amelia Bourdeau, director of foreign exchange at Westpac Institutional Bank, agrees. "Andy's correct," she told CNBC's Melissa Lee. "If Germany does not pass this, everyone head for the hills. It's going to be really, really bad."

To trade on all these risk events, Busch recommends selling the euro against the dollar.

If Germany votes yes - which Busch expects they will - he says there could be a bounce in the single currency, which would give you a chance to get into the trade at a nice level before the overriding risk-averse market sentiment takes over again. In that case, he would sell the euro at 1.38 with a stop at 1.3975 and a target of 1.32. If Germany votes no, he would sell the euro at lower levels, like 1.35.

Patterson likes the trade. "I like selling euros on rallies," she says. "It's been my flavor of the month for several months now."